Lathe-dog



R. W. LOFSTROM.

LATHE DOG.- APPLICATION FILED SEPT. 10, 1919.

1,342, 122, I v Patented June 1, 1926.

UNITED STATES mm OFFICE. I

ROBERT W. LOFSTROM, 0F WORCESTER, MASSACHUSETTS,

LATHE-DOG.

To all whom it may concern:

Be it known that I, ROBERT W. LOFSTROM, a citizen of the United States,residing at Worcester, in the county of Worcester and State ofMassachusetts, have invented a new and useful Lathe-Dog, of which thefollowing is a specification.

This invention relates to a lathe dog and preferably one formedsubstantially in the ordinary well-known manner.

The principal objects of the invention are to provide a simple andinexpensive guard I which will prevent all parts of the dog coming intocontact with the workmens fingers under practical conditions to which itmay be subjected and so built as to include the dog and eliminateprojecting parts as Well as perforations and passages into which thehand or a tool might he accidentally introduced; also to provide incombination therewith, means for attaching the dog to the face platewhen it is desired to draw back the tail stock for any purpose so thatthe work will remain accurately centered. This latter object isaccomplished by means of hooks cooperating with certain features of theguard plate which can be provided very easily and inexpensively inconnection with the construction above described. Further objects andadvantages of the inventionwill appear hereinafter.

Reference is to be had to the accompanying drawings, in which- Figure 1is a plan viewof a preferred form of this invention shown as applied toa piece of work centered on a lathe;

Fig. 2 is a side view ofthe dog with a part broken away to show theinterior construction and illustrating the manner of tightening up thedog on the work; and

Fig. 3 is a rear elevation- The invention is shown as embodying a dog 10substantially of the usual well-known shape and construction. It isprovided with a main portion having a passage 11 therethrough for thework, a screw 12 for tightening it up against the work C, and a tail 13for engagement with the face plate or the like. These parts, as stated,can be of the ordinary shape and material without alteration, but I haveprovided this dog with four flanges 14, in the form shown, by which itis attached by means of rivets 15,to a guard plate 16.

The guard plate is made preferably of thin sheet metal and provided withan in- Specification of Letters Patent.

Patented June 1, 1920.

Application filed September 10, 1919. Serial No. 322,805.

tegral flange 17 formed in dies as will be readily understood. It isapplied to the face of the dog farthest from the face plate A. The plate16 preferably is perfectly fiat on its outer surface and it extendsinwardly at the center to the boundary of the passage 11 and has apassage through it registering with, and of the same size and shape asthat passage. These two being riveted together, are thereaftersubstantially a single piece, and of course, are never separated inpractice. It will be observed that the tail 13 is protected at one endby this flange 17 which extends around that part of the tail and beyondit.

The parts so far described constitute a single unitary construction withno movable,

parts except the usual screw 12 and the plate constitutes a rotatingelement with smooth outer surfaces mounted substantially concentricallyon the work so that it affords neither projections nor passages by whichthe workman can be injured. All parts of the dog and this screw areprotected and very little expense added. In the form shown, the screw isoperated by the usual wrench B through an opening 19- in the flange 17.

For the purpose of keeping the work C centered when the tail stock is tobe moved back for any purpose, I have provided the flange 17 with twosmall perforations made by punching inwardly two tongues 20, the shapeof which will be obvious from Fig. 1. They furnish lugs behind whichhooks 21 can be attached for holding the whole device up in centralposition. Two of these hooks are shown extending through the face plateA and adjusted in position by a nut 22 and plate 23. In this way, thework can be held in central position, even when not supported at theopposite center, that end of the work being upheld by the center-restand the attachment for this purpose is provided in a most simple andinexpensive manner in connection with the guard.

It is to be noted that this guard protects all parts of the dogincluding the screw 12, leaving no chance for it to catch hold ofanything when in rotation. It is very easy to fasten in place, not beingany more complicated in this respect than the ordinary dog and is alsoeasy to fasten to the face plate, by means of the hooks 21. In fact, ifthese hooks should be lost, it can be fastened by two wires or otherordinary de-.

vices that are usually found in a machine shop. The screw canbe turnedup by a socket, fork or S Wrench. The manner of attaching the guard tothe dog is such that the attachment will be extremely strong even if theguard is made of relatively light sheet metal, because the holes in theflanges and in the sheet metal are both countersunk 'and thiscounter-sinking on the dog can be made quite deep, so parts of the stockaround the holes of the guard will sink into the counter-sinking of thedog. Thus the parts will not work loose or fall apart under anyordinaryusage.

It will be understood of course, that instead of riveting, the two partscan be put together by brazing or welding or the Whole device can becast in one piece if the guard is made heavier. It is an importantadvantage to have the whole device consist of a single piece, andalso itis an advantage that the device takes'up' practically no space inaddition to that taken up by the ordinary rotating dog.

AlthoughI have illustrated onlya single form of the. invention, I amaware of the fact that many modifications can be made therein and thatit can be made in other forms and of other materials than those shownand described. Therefore I do not wish to be limited in these respects,but what I. do claim is 1. As an article of manufacture, a lathe doghaving a passage for the work, an integral tail, and flat externalflanges on both sides of said passage in a plane, and provided with asheet metal guard plate riveted to said dog through said flanges, saidplate being provided with a flat outer surface on one side of the dog,and having a passage therethrough registering with said passage in thedog, but otherwise imperforate, and having an integral cylindricalflange inclosing'said dog and located outside the tail to protect it,

projecting inwardly and protected by theflange, and means for engagingsaid lugs and holding the protecting plate to the face plate of thelathe in a central position.

3'. The combination of a lathe dog having a passage for the work and atail, a guard plate fixedly connected to said dog, said plate comprisinga flat outer surface on one side of the dog and having a passagetherethrough registering with said passagein the dog and having acylindrical flange inand extending beyond it said flange having inwardlyextending lugs, and hooks for engaging said lugs and the lathe faceplate and holding the dog and guard plate fixed in position to keep thework centered when held only by the head stock and the center rest.

4:. The combination with a guard plate for a .lathe dog having integrallugs inside the same, of means for engaging said lugs and-holding theguard plate to the face plate.

5. The combination with a guard plate for a lathe dog, of a pair'ofhooks adapted to be supported by a faceplate and means on the guardplate and protected thereby for engaging said hooks.

In testimony whereof aflixed my signature.

ROBERT WV. LOFSTROM I have hereunto

